Global navigation satellite systems (GNSS) are broadly defined to include GPS (U.S.), Galileo (proposed), GLONASS (Russia), Beidou (China), IRNSS (India, proposed), QZSS (Japan, proposed) and other current and future positioning technologies using signals from satellites, with or without augmentation from terrestrial sources. Information from GNSS is being increasingly used for computing a user's positional information (e.g., a location, a speed, a direction of travel, etc.).
In GNSS, multiple satellites may be present, with each transmitting a GNSS signal. A received signal at a GNSS receiver contains one or more of the transmitted GNSS signals. To obtain the information from the respective transmitted signals, the GNSS receiver performs a signal acquisition/tracking procedure. More specifically, the GNSS receiver searches for the corresponding transmitted signals in the received signal and then locks onto them for subsequent tracking of the corresponding satellites to receive the satellite information.
The signal acquisition/tracking procedure often entails correlating the received signal (typically down-converted to baseband) with a corresponding local signal generated within the GNSS receiver. Since time required by the GNSS receiver to determine the positional information is dependent on time consumed in performing the signal acquisition/tracking procedure, sizable area and power consumption in the GNSS receiver is dedicated to the signal acquisition/tracking components in the GNSS receiver.